Our understanding of the universe has changed a lot over time. People in many cultures have been observing the sky for thousands of years. The Egyptians created tools to track the movements of the stars, as did the ancient Babylonians. Of the all the ancient civilizations that studied the stars, the ancient Greeks were probably the most influential.

The ancient Greeks, particularly an astronomer named Ptolemy, thought the universe contained only Earth at the center, the Sun, the Moon, five planets, and a sphere to which all the stars were attached. Most people had this basic idea of the universe for centuries. It was not until the Middle Ages and Renaissance that this idea was questioned.

Sources
http://www.windows.ucar.edu (permits educational or research, but not commercial purposes)
David Bethel http://ck12.org/flexr/assemble/?fid=732 (CC BY-SA)